//: C25:Visitor.h
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// The base interface for visitors
// and template for visitable Trash types
#ifndef VISITOR_H
#define VISITOR_H
#include "Trash.h"
#include "Aluminum.h"
#include "Paper.h"
#include "Glass.h"
#include "Cardboard.h"

class Visitor
{
public:
    virtual void visit(Aluminum* a) = 0;
    virtual void visit(Paper* p) = 0;
    virtual void visit(Glass* g) = 0;
    virtual void visit(Cardboard* c) = 0;
};

// Template to generate visitable
// trash types by inheriting from originals:
template<class TrashType>
class Visitable : public TrashType
{
protected:
    Visitable () : TrashType(0) {}
    friend class TrashPrototypeInit;
public:
    Visitable(double wt) : TrashType(wt) {}
    // Remember "this" is pointer to current type:
    void accept(Visitor& v) {
        v.visit(this);
    }
    // Override clone() to create this new type:
    Trash* clone(const Trash::Info& info) {
        return new Visitable(info.data());
    }
};
#endif // VISITOR_H ///:~
